齐型空间上的Toeplitz型算子

设X是齐型空间.设T_(j,1)和T_(j,2)是具有非光滑核的奇异积分算子,或者是±II(I是恒等算子).令Toeplitz型算子T_b=■T_(j,1)M_T_(j,2),其中M_bf(x)=b(x)f(x).研究了当b∈BMO(X)时,T_b(f)在加权情况下的有界性,以及当b∈BMO(X)时,与经典Carderon-Zygmund算子相联的T_b(f)在Morrey空间上的有界性.     

Semi-metallic single-component crystal of soluble La@C82 derivative with high electron mobility

We prepared an organic conductor crystal having extremely high electron mobility, in which the adamantylidene (Ad) derivative of La@C(82) (an endohedral metallofullerene known as a n-type semiconductor) is aligned in an orderly fashion. The single-component crystal exhibits high electron mobility of μ > 10 cm(2) V(-1) s(-1) along the c axis under normal temperatures and pressures in the atmosphere, as shown by flash-photolysis time-resolved microwave conductivity (TRMC) measurements, which are the highest of reported organic conductors measured by TRMC. According to density functional calculations, the single crystal of La@C(82)Ad is semi-metallic, with a small band gap of 0.005 eV.     

Preparation and properties of Ni-doped ZnO rod arrays from aqueous solution

Ni-doped ZnO rod arrays were successfully prepared on glass substrate from the aqueous solution at a temperature of 80 °C. The densities, diameters, and lengths of the rods can easily be well controlled through the concentrations of dopants, and the dopant Ni ions were incorporated into the wurtzite-structure of ZnO crystal. Room temperature photoluminescence spectrum of rod arrays show a strong emission band at 410 nm, and the oxygen deficiencies in ZnO structures were significantly reduced with Ni doped in ZnO rod arrays. The field dependence of magnetization measured at room temperature exhibited the obvious ferromagnetic properties.     

COMPOSITION OPERATORS ON HARDY-ORLICZ SPACES

Properties of composition operators induced by analytic self-maps on the unit disk of the complex plane in Hardy-Orlicz spaces are discussed. Results are concerned about boundedness, invertibility, compactness, Fredholm operators and spectra of composition operators.     

Preparation and characterization of the biomineralized zinc oxide particles in spider silk peptides

In this work, hierarchical ZnO particles were prepared using a biomineralization strategy at room temperature in the presence of peptides acidified from spider silk proteins. A mechanism of the mineralization of the ZnO particles was that the affinity of original ZnO nanoparticles and zinc ions in the peptide chains played an important role in controlling the biocrystallizing formation of the pore ZnO particles. The intensity of their visible green luminescence was enhanced with increases of the mineralization time due to the porous surface defects. The hierarchical ZnO materials with biomolecules will facilitate their photoluminescence spectra applications as biosensors or optoelectronic nanodevices in the future, when covalently coupled with peptides or other biomolecules to achieve patterned growth over large areas of substrate.     

First-principles study of the four polymorphs of crystalline octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

The electronic structure and vibrational properties of the four polymorphs of crystalline octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) have been studied using density functional theory within the local density approximation. The results show that the states of N in the ring make more important contributions to the valence bands than these of C and N of NO2 and so N in the ring acts as an active center. From the low frequency to high-frequency region, the molecular motions of the vibrational frequencies for the four HMX polymorphs present unique features. It is also noted that there is a relationship between the band gap and impact sensitivity for the four HMX polymorphs. From the cell bond order per unit volume, we may infer the variation order of crystal bonding for the four polymorphs and so predict their impact sensitivity order as follows: beta-HMX < gamma-HMX < alpha-HMX < delta-HMX, which is in agreement with their experimental order.     

Cationic corrole derivatives: a new family of G-quadruplex inducing and stabilizing ligands

Water-soluble cationic corrole derivatives were designed and synthesized, and the first observation of their interactions with the telomeric G-quadruplex was made.     

Investigation of the synergistic effect with chiral D-penicillamine functionalized gold nanoparticle as an additive for enantiomeric separation in capillary electrophoresis

The authors describe a synergistic system for nanoparticle based chiral separation. It is based on the use of a conventional chiral selector hydroxyproyl-β-cyclodextrin and a kind of gold nanoparticle functionalized with D-penicillamine as an additive. This nanomaterial displays a synergistic effect on the efficiency of the enantioseparation of the chiral drugs amlodipine, tropicamide, and ofloxacin. A comparative study on the enantioseparation capability of three separation systems, viz. (a) single hydroxyproyl-β-cyclodextrin system, (b) achiral citrate capped gold nanoparticle/ hydroxyproyl-β-cyclodextrin system, and (c) chiral D-penicillamine functionalized gold nanoparticle/ hydroxyproyl-β-cyclodextrin system was performed. The results show that the D-penicillamine functionalized gold nanoparticle/hydroxyproyl-β-cyclodextrin synergistic system has remarkable superiority. The effects of concentrations of D-penicillamine functionalized gold nanoparticle and hydroxyproyl-β-cyclodextrin, of buffer pH value and concentration, and of applied voltage on the performance of enantioseparation were investigated.     

低温空气制冷系统中板翅换热器性能实验研究

对低温空气制冷系统中的散热器、回热器性能进行实验研究,测量不同工况条件下两个锯齿形板翅式换热器的换热效率及系统性能,分析了换热器低压侧和高压侧的空气流量对换热器及系统性能的影响。结果表明:(1)散热器低压侧空气流量是影响其效率的主要因素;(2)回热器效率随其低压侧空气流量的增大而增大,随其高压空气流量的增大而减小;(3)高压空气流量是影响制冷量的主要因素;在其它工况参数不变的条件下,高压空气流量增大7.9%,制冷量最大增加14.5%。